Budget-constrained maintenance in the building industry

Given records of building component renewals which occurredduring the year and also theage profile of the building stock,the theory of alternating renewal processes in discrete timeis used to deduce the underlying probability mass functionsof the natural lifespan of building components and of delaydue to limited resource. In an investigation into the economicsof renewal delay, the expected number of component renewalsin each year of the life of a building is deduced from the convolutionsof the probability mass function of natural lifespan: theseexpected numbers depend on the chosen delay. The nett presentvalue of the expected cost associated with each specified delayis calculated, so that a judgement can be made as to the optimumdelay (if any). These calculations are conveniently performedusing a spreadsheet macro.